Date.prototype.format = function(fmt) {

	var o = {

		"M+": this.getMonth() + 1, //月份 

		"d+": this.getDate(), //日 

		"h+": this.getHours(), //小时 

		"m+": this.getMinutes(), //分 

		"s+": this.getSeconds(), //秒 

		"q+": Math.floor((this.getMonth() + 3) / 3), //季度 

		"S": this.getMilliseconds() //毫秒 

	};

	if (/(y+)/.test(fmt)) {

		fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));

	}

	for (var k in o) {

		if (new RegExp("(" + k + ")").test(fmt)) {

			fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));

		}

	}

	return fmt;

}

var sDay = "";
Date.prototype.startDay = function(fmt,timeStatus) {
	if(timeStatus == "set"){
		sDay = fmt;
		return "";
	}else if(timeStatus == "get"){
		return sDay;
	}else{
		sDay = null;
		return "";
	}
}
